本地新建文件 ElidedLabel.h、ElidedLabel.cpp, 复制代码到文件中, 把 ElidedLabel 当做 QLabel 使用即可.

    1. #ifndef ELIDEDLABEL_H
    2. #define ELIDEDLABEL_H
    4. #include <QLabel>
    5. #include <QObject>
    6. #include <QLabel>
    8. class ElidedLabel : public QLabel
    9. {
    10. Q_OBJECT
    11. using QLabel::QLabel;
    13. public:
    14. explicit ElidedLabel(QWidget *parent=nullptr);
    16. // Set the elide mode used for displaying text.
    17. void setElideMode(Qt::TextElideMode elideMode);
    18. // Get the elide mode currently used to display text.
    19. Qt::TextElideMode elideMode() const { return m_elideMode; }
    21. protected:
    22. void paintEvent(QPaintEvent *e) override;
    23. void resizeEvent(QResizeEvent *e) override;
    25. private:
    26. void updateCachedTexts();
    28. private:
    29. Qt::TextElideMode m_elideMode = Qt::ElideRight;
    30. QString m_cachedElidedText;
    31. QString m_cachedText;
    32. };
    34. #endif // ELIDEDLABEL_H
    1. #include "ElidedLabel.h"
    3. ElidedLabel::ElidedLabel(QWidget *parent)
    4.     : QLabel(parent)
    5. {
    7. }
    9. void ElidedLabel::setElideMode(Qt::TextElideMode elideMode)
    10. {
    11.     m_elideMode = elideMode;
    12.     m_cachedText.clear();
    13.     update();
    14. }
    16. void ElidedLabel::paintEvent(QPaintEvent *e)
    17. {
    18.     if (m_elideMode == Qt::ElideNone)
    19.            return QLabel::paintEvent(e);
    21.    updateCachedTexts();
    22.    QLabel::setText(m_cachedElidedText);
    23.    QLabel::paintEvent(e);
    24.    QLabel::setText(m_cachedText);
    25. }
    27. void ElidedLabel::resizeEvent(QResizeEvent *e)
    28. {
    29.     QLabel::resizeEvent(e);
    30.     m_cachedText.clear();
    31. }
    33. void ElidedLabel::updateCachedTexts()
    34. {
    35.     // setText() is not virtual ... :/
    36.     const auto txt = text();
    37.     if (m_cachedText == txt)
    38.         return;
    39.     m_cachedText = txt;
    40.     const QFontMetrics fm(fontMetrics());
    41.     m_cachedElidedText = fm.elidedText(text(),
    42.                                      m_elideMode,
    43.                                      width(),
    44.                                      Qt::TextShowMnemonic);
    45.     // make sure to show at least the first character
    46. //    if (!m_cachedText.isEmpty())
    47. //    {
    48. //        const QString showFirstCharacter = m_cachedText.at(0) + QStringLiteral("...");
    49. //        setMinimumWidth(fm.horizontalAdvance(showFirstCharacter) + 1);
    50. //    }
    51. }

    代码来源：https://wiki.qt.io/Elided_Label